* Mary Boleyn: The titular "other Boleyn girl," she is the elder sister of Anne Boleyn. Mary is ambitious and cunning, seeking power and social advancement. She becomes the mistress of both King Henry VIII and his brother, King Francis I of France.
* Anne Boleyn: Mary's younger sister and the future Queen of England. She is a strong-willed and intelligent woman who desires love and respect, not just power.
* King Henry VIII: The King of England, he is a complex and often ruthless figure, driven by his desire for a male heir and his passion for Anne Boleyn.
* George Boleyn: The brother of Mary and Anne, he is a cunning and ambitious figure who is loyal to his family. He is involved in various intrigues and plots at the court.
* Thomas Boleyn: The father of Mary and Anne, he is a powerful nobleman who uses his daughters' beauty and influence to climb the social ladder.
* Elizabeth Boleyn: The mother of Mary and Anne, she is a more passive figure who is caught in the middle of the family's power struggles.
These are the primary characters, but there are other important figures like:
* Jane Seymour: A rival of Anne Boleyn and ultimately Henry VIII's third wife.
* Cardinal Wolsey: The King's chief advisor who is eventually overthrown.
* Thomas Cromwell: A rising political star who is initially a close ally of Henry VIII.
The story revolves around the complex relationships between these characters, their ambitions, and the struggles for power and love in the Tudor court.